Poly (ether) urethane close/open cell (PEUCC/PEUOC) has been prepared by using in situ polymerization approach. The third-order optical nonlinearities of dissolved samples in DMF were characterized by Z-scan technique at the measurement wavelength of 532 nm. The synthesized samples were also examined by optical microscopy and UV-Vis absorption spectroscopy. The nonlinear refractive (NLR) indice...

the mössbauer spectra of nanoferrite materials such as ni0.25mn0.75fe2o4, co0.5mn0.5fe2o4 and ni0.4co0.6fe2o4 have been reported and the above materials were prepared by sol-gel combustion method using metal nitrates as source material and polyvinyl alcohol(pva) as agglomeration reducing agent. as the structural, thermal and magnetic properties (vsm) of the above ferrites have been published al...

Perturbation theory is used to calculate the frequency shift of acoustic modes of an homogeneous turbulent fluid and the frequency shifts of solar modes due to turbulent convection. For sound waves in a random flow, the fractional frequency shift is +(11/30)M in the long-wavelength limit, and the shift at short wavelengths is −(2/3)M2, where M is the average Mach number of the flow. In our mode...

The spectral characteristics of lactose repressor protein modified with two nitrophenol reporter groups have been determined. Reaction of Z-chloromercuri-4nitrophenol with repressor increases the apparent pK of the nitrophenol from 6.75 to 8.3 and alters the wavelength of maximum absorption. Subsequent binding of inducer shifts the apparent pK toward slightly more acid pH. The pK values of the ...

--In low dispersion fibers, FWM spectrum is symmetric around the zero dispersion point. Wavelength shift keying technique using symmetric wavelengths and balanced detection can cancel FWM crosstalk to first order. Wavelength division multiplexing (WDM), zero or low dispersion fibers, and Er-doped fiber amplifiers are being used in long-haul communications links to increase capacity and to exten...

This paper concerns a wavelength-swept fiber laser (WSFL) incorporating frequency shifted feedback and an intracavity passband filter, in which the wavelength of the modeless output is linearly, continuously and repeatedly tuned (in time) over a given range by modulation of the filter peak wavelength and filter strength. We show both numerically and experimentally that amplifier noise plays a k...

Polarization insensitive wavelength conversion of a 40 Gb/s non-return-to-zero (NRZ) differential phase-shift keying (DPSK) data signal is demonstrated using four-wave mixing (FWM) in a silicon nanowire circuit. Polarization independence is achieved using a diversity circuit based on polarization rotators and splitters, which is fabricated by a simple process on the silicon-on-insulator (SOI) p...

We explore theoretically the possibility of generating broadband blue light by copropagating a short soliton pump pulse and a broader signal pulse in a microstructured fiber with a zero-dispersion wavelength located between the center wavelength of the pump and the signal pulses. We show that the unique properties of microstructured fibers should allow for broadening of the signal pulse's spect...

Dual-beam-scan Doppler optical coherence angiography (DB-OCA) with a 1-μm-wavelength probe is demonstrated for improved in vivo choroidal angiograms of the human eye. This method utilizes two scanning beams with spatial and temporal separation on the retina, and provides two measurable velocity ranges. The method achieves higher sensitivity to very low velocity flows than conventional Doppler o...

We show that a buried oxide layer forming a current aperture in an all epitaxial vertical-cavity surface emitting laser has a profound influence on the optical and electrical characteristics of the device. The lateral index variation formed around the oxide current aperture leads to a shift in the cavity resonance wavelength. The resonance wavelength under the oxide layer can thus be manipulate...